MCEC Jubileum Celebration – Abstracts |

Prof. Raffaella Ocone – Heriot-Watt University

The Rheology of Granular Materials

Granular materials exhibit a broad range of intricate dynamic behaviours. In the chemical and process industries, where those materials are widely handled and produced, studying their hydrodynamics is of critical importance. Indeed, understanding how internal (e.g., particles size and shape) and external (e.g., applied stresses, moisture content) physical properties impact on the flow behaviour of solid particles helps industrial practitioners handle and produce particulates in an efficient and less costly way.

The talk will explore the challenges that the dynamic behaviour of dry and wet granular materials poses and discusses the most recent experimental and modelling studies undertaken at Heriot-Watt University. Those studies aim at elucidating the rheological behaviour of aerated granular materials by employing a commercial instrument, the Freeman FT4 Powder Rheometer, which is modified to generate Couette flow. We call the modified instrument the “Aerated Bed Virtual Couette Rheometer” (AB-VCR) and its development is presented. The AB-VCR is employed in both non-aerated and aerated modes to determine the rheology of monodispersed spherical glass beads with and without moisture. Systematic measurements of the stresses which develop within the granular medium are presented and a rheological law is proposed. The validity of such a constitutive law is tested and discussed.

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